C. The cart must travel a greater distance along the incline than the block travels as it falls.
This is correct because the incline is large than the direct distance of the block
B. The average speed of the block as it falls is greater than the average speed of the cart as it travels the length of the incline.
This is correct, due to the total speed is the sum of both directions, one is moving on y-axis and the other is on the y and x-axis